The invention is directed to improvements in a fuel supply system for a fuel injection system.
A fuel supply system of an internal combustion engine, preferably in a motor vehicle, typically includes a plurality of units. In the fuel supply system, a fuel pump pumps fuel from a fuel reserve out of a fuel reserve container via various units, until the fuel finally reaches a combustion chamber of the engine. One of the units is for instance a pressure regulator, a fuel reservoir, a pressure damper, a fuel filter, or a fuel injection valve.
It can happen that one of the units, for instance the pressure regulator itself or a component of that unit, is electrically conductive, yet the electrically conductive component or the unit is disposed in electrically insulated fashion, for instance because the unit is disposed on a base body that comprises non-conductive plastic.
German published, nonexamined patent application DE 44 02 224 A1 shows one such unit downstream of a fuel pump. Here, a pressure regulator is integrated with a body made of plastic. The pressure regulator has a housing part made of sheet metal. This housing part is an electrically conductive component, which has no electrical connection with an electrical conductor that forms a defined electrical potential.
In the unit having an electrically conductive component, electrostatic charging of the electrically conductive component can occur from electrical charge separation. Because typically the electrostatic charging of the electrically conductive component causes no problem and in particular no disruption in function, normally the electrostatic charging of the electrically conductive component is not noticed, or at least not taken into account. Because there are units through which the fuel flows through a narrow gap, for instance at a high flow velocity, as in a pressure regulator, the electrostatic charging of the electrically conductive component can be quite pronounced.
Sometimes, fortunately quite rarely, it could happen that a fire or explosion whose cause cannot be explained will occur in a fuel supply system. The inventors of the present patent application are of the opinion that at least some of these unexplainable fires have been caused by electrostatic charging of an electrically conductive component of a unit in the fuel supply system.
It is a principal object of the invention to provide a fuel supply system having the advantage over the prior art that electrostatic charging of the electrically conductive component is prevented, and any source of danger it might cause is eliminated.
Other objects of the invention will become apparent upon a review of the drawings in connection with the specification hereinafter.